1. Field of the Invention
The present invention generally relates to an image forming apparatus, such as a wet-type electrophotographic printer, using liquid developer. More particularly, the present invention relates to a fitting protecting apparatus of a developer cartridge for protecting a connection fitting of a developer cartridge for storing and supplying liquid developer, and to an image forming apparatus having the same.
2. Description of the Related Art
An image forming apparatus, such as a wet-type electrophotographic printer, typically includes a developer supply system for supplying liquid developer to a developing part. The developer supply system may be either a one-body type in which a developer cartridge is formed in one body with a developing part, and a separation type in which a developer cartridge is separated from a developing part through a connection with a connection tube.
In a separation type developer supply system, liquid developer is supplied from a developer cartridge to a developing part and is recollected from the developing part to the developer cartridge through a connection tube by using a developer supply pump and/or a developer re-collection pump. The developer cartridge is connected to the connection tube through a coupling part such as a fitting.
FIG. 1 schematically illustrates a general wet-type electrophotographic printer 10 employing a separation type developer supply system.
Referring to FIG. 1, the wet-type electrophotographic printer 10 includes an image forming part 11 and a developer supply part 21.
The image forming part 11 includes a photoconductive body 1, such as an OPC drum (Organic Photoconductive Drum), a laser scanning part 33, a charge part 6, an antistatic part 7, a developing part 26 and a cleaning blade 8. These components mutually work and provide a desired image to the photoconductive body 1 through sequential image formation procedures such as charge, discharge, and exposure and developing procedures.
The developing part 26 includes a developing chamber 27 through which liquid developer 48 flows, a developing roller 2 disposed under the photoconductive body 1, a deposit roller 5 for applying electric force to the liquid developer 48 to form a charged developer layer around the developing roller 2, a metering roller 3 for limiting the charged developer layer formed around the developing roller 2 by the deposit roller to a predetermined toner volume or density (percent solid) and to supply the charged developer layer to a nip between the developing roller 2 and the photoconductive body 1, a cleaning roller 4 for cleaning the developing roller 2, and a recollection chamber 28 for recollecting liquid developer 48 overflowing from the developing chamber 27.
A developer supply part 21 is disposed to supply liquid developer 48 to a developing chamber 27 of the developing part 26.
The developer supply part 21 includes a developer cartridge 50 for storing liquid developer 48, first and second connection tubes 22 and 23 for connecting the developer cartridge 50 to a developing chamber 27 of a developing part 26, a developer supply pump 18 disposed between the first and second connection tubes 22 and 23, a developer recollection pump 19 disposed between third and fourth connection tubes 20 and 24, and a controller 29 for controlling motors of the developer supply pump 18 and the developer recollection pump 19.
With reference to FIG. 2, the developer cartridge 50 includes a housing 12 provided as a developer storage space for storing liquid developer 48, and a liquid developer agitator 35 for agitating the liquid developer 48 within the housing 12.
On an upper part of the housing 12, a first developer discharge part 17 and a first developer influx part 16 are installed. The first developer discharge part 17 is connected to a second developer influx part 13 of a developing chamber 27 of a developing part through first and second connection tubes 22 and 23, to supply liquid developer 48 of a housing 10 to the developing chamber 27. The first developer influx part 16 is connected to a second developer discharge part 14 of a recollection chamber 28 of the developing part 26 through third and fourth connection tubes 20 and 24, to recollect the liquid developer 48 from a recollection chamber 2.
The first developer discharge part 17 includes a first female fitting 17a, a developer suction tube 40, and a first male fitting 17b. The first female fitting 17a is disposed on the housing 12. The developer suction tube 40 is extended from the first female fitting 17a to the bottom of the housing 12. The first male fitting 17b is disposed at the end of the first connection tube to couple with the first female fitting 17a when the housing 12 is accommodated in a printer body (not shown).
The first developer influx part 16 includes a second female fitting 16a and a second male fitting 16b, as in the first developer discharge part 17. A configuration of the second female fitting 16a and the second male fitting 16b is the same as the construction of the first female fitting 17a and the first male fitting 17b, except that the suction tube 40 is not connected to the second female fitting 16a. 
However, by a structural characteristic of such a conventional wet-type printer 10, when a developer cartridge 50 is separated from the printer body for maintenance or when the developer cartridge is not installed in the printer body, a first female fitting 17a of a first developer discharge part 17 and a second female fitting 16a of a first developer influx part 16 are exposed. Developer stains on portions of the exposed first and second female fittings 17a and 16a are exposed to a user, and portions of the exposed first and second female fittings 17a and 16a may become polluted by outside foreign substances, such as dust and the like, or portions of the first and second female fittings 17a and 16a exposed in handling the developer cartridge 50 may be damaged by falling or an external collision.
In situations where developer stains on portions of the exposed first and second female fittings 17a and 16a are exposed to a user, the user may be further transfer such developer and secondarily pollute or stain other components of the printer.
When portions of the exposed first and second female fittings 17a and 16a are polluted with foreign substances, it is inconvenient to remove the foreign substances adhering on the portions of the polluted first and second female fittings 17a and 16a before installing the developer cartridge 50 in the printer body. Furthermore, if the developer cartridge 50 is installed in the printer body in a state that the foreign substances are not completely removed, the foreign substances may flow in the liquid developer 48, thus polluting the liquid developer 48 and lowering the quality of the image formed by a developing part 26.
Also, if portions of the exposed first and second female fittings 17a and 16a are damaged by outside collision, a sealing state between a first female fitting 17a and a first male fitting 17b of a first developer discharge part 17 and between a second female fitting 16a and a second male fitting 16b of a first developer influx part 16 is not optimal, thus causing leakage of liquid developer 48 and polluting its periphery.
Thus, a need exists for a fitting protecting apparatus for a developer cartridge of an image forming apparatus that protects a connection fitting of the developer cartridge that stores and supplies liquid developer.